Automatic contact printers for electrostatic reproductions



Jan. 8, 1963 H. MACKRODT 3,072,026

AUTOMATIC CONTACT PRINTERS FOR ELECTROSTATIC REPRODUCTIONS Filed March13, 1959 2 Sheets-Sheetl F/Gf1 20 22 14 14a 32 I 3 23 1a 26 5 .J I I .I

19 T I J INV ENT OR. HELMUT MACKRODT dim M121;

TORNEYS United States Patent r 3,072,026 AUTOMATIC CONTACT PRINTERS FORELECTRO- STATIC REPRODUCTIONS Helmut Mackrodt, Bonn, Germany, assignorto Messrs.

F. Soennecken, Bonn, Germany a corporation of Germany Filed Mar. 13,1959, Ser. No. 799,306 Claims priority, application Germany Mar. 18,1958 7 4 Claims. (Cl. 95-1.7)

The present invention relates to an automatic contact printer forelectrostatic reproductions, in which all devices for loading, exposing,colouring and fixing are combined in one apparatus.

With the prior known apparatuswhich operate by similar processes, theseparate working steps have generally to be carried out independentalyof one another and different copying plates likeswise have to be madeseparately.

3,072,026 Patented Jan. 8, 1963 slots and bends in the guide ductspermit a friction-less travel of the paper webs.

Adjustable high voltage charging devices are installed in the supplyducts for the electrostatic photographic paper and the print supports.By changing their spacing, the charging process can be adapted to theparticular ambient conditions such as air humidity and paper qualities.A trough-shaped container which isfilled with a suflicient quality oftoning agents which are known per se is provided for the development orcolouring of the charged and exposed separate sheets or paper webs. Thisand fixingmay be maintained or even interrupted at will as required, bytaking suitable measures when producing the electrostatic reproduction.Furthermore, originals or subjects printed onone or both sides or evenprovided with script and or drawings, etc., can be processed in theautomatic printer of the present invention by the transmitted lightprocess or by the reflex process. This is possible as the light-perviousprinting cylinder may be swivelled as desired, such as through an angleof 180", while keeping the same supply and delivery devices for both thesubjects or originals to be transferred and also forthe electrostaticphotographic paper. The direction of rotation of the entiresexposuredevice is automaticelly adapted to the necessary working method.

By this means, one-sided transparent originals or copies are guidedalong on the exposure cylinder while, with a swivelled exposure device,the electrostatic or electrophotographic paper travels along the saidcylinder and thus reflex copies can be produced.

Long supply and discharge ducts ensure the correct registry and thesmoothpassage of the separate sheets. By means of the blocking anddeflecting slides fitted into certain of the supply and discharge ducts,it is possible for a sheet of the electrostatic photographic paper onlyto be statically charged without exposing. While this is being done theexposure means is switched oil and the exposure is subsequently effectedoutside the apparatus. In this way a reproduction of for example onepage of a' book or. the like may be made using the statically chargedelectrophotographic paper, the sheet of the electrostatic photographicpaper exposed outside the apparatus being introduced through a secondslot into the apparatus where it is developed and fixed.

In order to be able exactly to cover the sheets of the said photographicpaper with the copying originals, a clocking means is arranged on thefeed means. This blocking means is so combined with the feed rollersthat an automatic advance of the separate sheets, which are supplied,takes place only when a mechanical or electrical actuation of the'feedrollers simultaneously causes the disengagement of the blocking means.

The apparatus can also be provided with a supplementarydevicewhichpermits papersin roll form to be used for electrostatic photographicpaper and print supports instead of single sheets. In this casedeflecting and sliding rollers which are provided at the inlet andoutlet container is so designed that the papers which are to becoloured, slide with their uncoated backs along the wall of thecontainer, and are positively supplied for the necessary additionalworking steps due to the curvature of the container Wall. Arranged inthe container itself is a bladed wheel which constantly circulates thetoner and' throws it simultaneously on to the surface of the paper webwhich is to be coloured. The flanges of the bladed wheel project beyondthe external diameter of the blades and serve simultaneously as guidesfor the paper sheets or webs.

current source. The polarity is so chosen as to be opposite to that ofthe charging voltage, which was used prior to the exposure process, inorder to guarantee a better adhesion of the powder elements to theexposed areas. The entire trough-shaped container can easily beextracted from the apparatus housing in order to clean and renderpossible a rapid replenishment with toner.

Ribs are provided on the inside wall of this trough-shaped trostaticallyadhering powder particles are thereby firmly fused thereon so that theycannot be wiped off. Electrical heating means are also installed in thesupply ducts for the paper sheets or webs, which means can be switched;

on if for example too high a degree of air humidity makes it necessaryfor the papers to be initially dried in other to produce goodelectrostatic reproductions.

The complete automatic contact printer with its guide ducts is assembledfrom components which can easily be removed, so that they can be veryquickly cleaned and access to the mechanical parts of the apparatus isassured in simplest possible manner.

In order to facilitate the operation and control of the separate workingsteps, the complete apparatus is constructed in the form of a desk, sothat all supply and discharge slots can be easily supervised.

Arranged at the supply slots of the guide ducts are signal lamps whichare so connected that with the different working methods for reflex andtransmitted light prints, the only slots used for each particular methodof working are those indicated by illumination with the lamps.

The invention is represented diagrammatically and in principle in thefiguresof the accompanying drawings. Details of the drive means for theelectrical devices are omitted for clarity in the drawings. a FIGURE 1is a longitudinal section through the automatic printer for usingseparate sheets,

FIGURE 2 shows a section through the ribs of the printer of FIGURE 1,

This bladed wheel is advantageously made of metal and connected to theterminal of a high voltage FIGURE 3 shows the pair of feed rollers withthe paper stop when in the disengaged position,

FIGURE 4 shows the same as FIGURE 3, but in the engaged position, a I tFIGURE 5 shows the automatic printer with a means for handling paper inroll form.

The automatic machine consists essentially of the housing 1, which iscomposed of a plurality of readily detachable components. However theseare not shown as such inorder to simplify the drawings. Theelectrostatic photograp'hic paper Iis inserted into the slot 2, and theoriginals or subjects to be printed II are inserted into the slot 3. Thepaper and the original are both advanced until they abut against thestop 4 of the feed means, which consists of the rollers 5 and 6. Thefeed means, which is shown in detail in FIGURES 3 and 4, consistsessentially of the fixedly mounted roller 5, the movable roller 6, theroller support 7 and the electromagnet 8, Which holds the movable roller6 away from the fixed roller 5 against the action of a helical spring 9.If now the holding circuit is opened by means of the switch 10, thespring 9 urges the holder 7 carrying the roller 6 downwards, whereby theforks 11 of the holder 7 depress the stop 4 against the action of aspring 12 and the two sheets of paper I and II are driven together andfed to the feed belt 13 which travels around the exposure cylinder 14 bymeans of the rollers 16, 17 and 18. The electrostatic photographic paperI has meanwhile been electrostatically charged at the high tensionstation 19. This high tension station consists of an adjustable andsubstantially U-shaped insulating component 20 slidable in th guideways21 and 22 the current-conducting wires 23 and also the diaphragm 24, andthe grounding rail 25. Depending on the nature of the original orsubject to be printed, the print may be made as a reflex copy by thefeed means consisting of the belt 13 and the rollers 16, 17 and 18 atthe exposure cylinder 14. On the other hand, the print may be made as atransmitted light copy after swivelling the feed means into the lowerposition, which is indicated in broken lines in FIGURE 1 by the rollers16, 17 and 18. The light is supplied by the fluorescent lamp 26 which isarranged in the centre of the exposure cylinder 14 and is covered by ascreen 14a. The complete exposure means assembly can be rotated aboutthe mean axisinto the position described above, the belt 13beingautomatically changed over to give the opposite direction oftravel. The exposed photographic paper and the original II nowtraveltogether into the feed means consisting of the rollers 27 and 28 and,after leaving the latter, are separated by a special separating device29, whereupon the original II discharges through the slot 30 while thephotographic paper is introduced through the wall 31 into thetrough-shaped developing tank 32 and slides along the wall thereof onthe ribs 33, shown in FIGURE 2. The flanges 34 of the bladed wheel 35take over the lateral guiding action at this point. The bladed wheel 35circulates the toner (not shown) and throws it against theelectrostatically charged and exposed surface of the photographic paper,the powdeiof the oner remains adhering to the paper due to thelectrostatic charging. This effect is further strengthened by thebladed wheel 35 advantageously being made of metal and being connectedto a voltage source having a polarity opposite to that of thehigh-tension station 19'. A uniform and economic consumption of thepowder is obtained by this circulation of the toner. Meanwhile, theprint support III or the transfer paper has been introduced into theslot 36 and electrostatically charged at a second high-tensionstation37. However, this second high-tension station 37 may be omitted withoutappreciably impairing the method of operation.

Due to the feed device 38, which can be switched on and which isconstructed similarly to that shown in FIG- 'URES 3 and 4, the sheet ofthe print support III is fed by electric control and synchronously withthe electrostation photographic paper which has now been introduced. Thesupport III and the paper I is brought into close contact by a pair ofrollers 39 and 40, so that the colouring powder adhering to the saidpaper I is transferred to the copy support III. Due to the guidingdirection into the contact rollers 39 and 40 being vertically upwards,all excess powder particles which are not electrostatically combinedfall off, so that clear and satisfactory prints are obtained without thehitherto usual beating and stripping devices having to be additionallyinstalled. After leaving the pair of rollers 39 and 40, the two sheetsare separated from one another by the separating device 41 and fed outthrough the slots 42 and 43. Here they slide past a heating means 44which supplies such a quantity of heat that the colouring powder isfixed by fusion onto the paper so that it cannot be wiped off. Thiscoinpletes the copying process.

In order to be able to carry out the entire working process when thepapers have taken up somewhat too much moisture, for example from theambient air or due to storage, heating elements 45, 46 and 47 whichbring the paper being used to the most favourable degree of dryness arearranged in the feed ducts 2, 3 and 36. v

If a reproduction is to be made of the page of a book or of anotherprinting subject which cannot be inserted in the machine, the slide 49is pushed down into the position shown in broken lines and theelectrostatic photo graphic paper I is introduced in the usual way intothe slot 2, where it is statically charged in passing through thehigh-tension station 19' in the manner previously described and is bentaround the lower bend of the slide 49 and thus discharges out'from theslot 48. The exposu're can then be made outside the apparatus. For thepurpose of developing such a paper, the slide 50 is also pushed downinto the position shown in broken lines, the now exposed paper isintroduced into the slot 51 and conveyed by the pair of rollers 27' and28 into the colour medium container 32. At the same time, the printsupport III is introduced at the slot 36 and is also electrostaticallycharged by passing through the hightension station 37. By makingelectrical contact in a manner not shown, the feed is initiated aspreviously described and the stop of feed means 38 equivalent to thestop 4 of FIGURES 3 and 4 is disengaged, so that once again the printsupport III travels in synchronisrn with the sheet of electrostaticpaper I, which is now coloured. The transfer of the reproduction and thefixing thereof takes place as previously described.

, For working with paper in roll form, the apparatus shown in FIGURE 1is placed on a roll carrier 52 according to FIGURE 5, which carries thetake-up reels 55 and 56 in addition to the supply roll 53 for theelectrostatic: photographic paper I and supply roll 54 for the printsupport III. In addition, guide rollers 57 to 65 are arranged on wallsor frames which are not shown and which are: not connected to the rollcarrier 52, these rollers 57 to 65 guiding the paper webs and conveyingthem corresponding to the previously described working operation. Theoriginals or subjects to be printed are supplied at the: slot 3 anddischarge at the slot 30. The paper webs for the print support III areintroduced into the apparatus. through the slot 36. The workingprocedure is the same as previously described. Here also, reflex ortransmitted light copies can be prepared, according to the nature of theoriginals or subjects to be printed. It is only the exposure cylinderwhich has to be turned to the'required position.

By providing feed devices known per se, fully automatic operation can beachieved.

Electric signal lamps (not shown) indicate inall cases the feed slots tobe used, so that the incorrect operation is substantially avoided.

Since the subject of the invention has bnly been dealt withdiagrammatically and as regards principles, it is of.

course obvious that variations in construction of the details arepossible, and thes also come within the scope of the claims.

What I claim is:

1. An electrophotographic copying apparatus including a housing,photographic exposure structure within the housing, a first ductextending from a wall of the housing to a feed zone adjacent theexposure structure, electrostatic charging elements within said duct, asecond duct extending from a wall of the housing to a location adjacentthe feed zone, feed mechanism in the feed zone connected to receivesheets from both ducts and pass them together along an exposure pathwhere they cooperate with the exposure structure to cause an image onone sheet to be photographically exposed on the other sheet, adjustablediversion structure movably positioned adjacent the feed zone so that itcan be inserted in and withdrawn from zone, and a passageway from thefeed zone to the exterior of the housing, said passageway cooperatingwith the diversion structure to cause a sheet moving through the firstduct to be deflected through said passageway and out of the housingwithout being photographically exposed, when the diversion structure isinserted in the feed zone.

2. The combination of claim 1 in which the housing also includesdeveloping mechanism, an additional passageway connects the developingmechanism with the exposure structure for guiding photographicallyexposed sheets through a developing operation, and a third passagewayconnects the additional passageway to the exterior of the housing forreceiving a sheet that is photographically exposed outside the housingand leading such externally exposed sheet to the developing mechanism.

8. An electrophotographic copying apparatus including a housing,photographic exposure structure within the housing, duct means extendingfrom the external surface of the housing to a feed zone adjacent theexposure structure, the exposure structure having a light-perviouscylinder mounted for rotation around its cylindrical axis and having alighted interior for photographically exposing sheets that are fedthrough the duct means and moved along its periphery, said structurealso including holding elements connected for mounting adjacent onecircumferential portion of the cylinder rotation to hold a pair ofsuperimposed sheets together and move them from the feed zone around thecylinder in one rotary direction so that the lower sheet is against thecylinder and is exposed in a reflex manner in accordance with anoriginal on the upper sheet, the holding elements being swiveled withrespect to the cylinder rotation for shifting to an opposed portion ofthe rotation path for holding and moving a pair of superimposed sheetsfirom the feed zone around the cylinder in the opposite rotary directionso that the upper sheet is against the cylinder and the lower sheet isexposed in a non-reflex manner in accordance with an original on theupper sheet.

4. The combination of claim 3 in which the holding elements include abelt that is pressed against the cylinder, driving means actuates thebelt for rotation with the cylinder, and a receiving passageway openingadjacent the cylinder receives the exposed sheets regardless of whichway they are moved around the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS2,551,582 Carlson May 8, 1951 2,624,652 Carlson Jan. 6, 1953 2,826,168Grant l Mar. 11, 1958

1. AN ELECTROPHOTOGRAPHIC COPYING APPARATUS INCLUDING A HOUSING,PHOTOGRAPHIC EXPOSURE STRUCTURE WITHIN THE HOUSING, A FIRST DUCTEXTENDING FROM A WALL OF THE HOUSING TO A FEED ZONE ADJACENT THEEXPOSURE STRUCTURE, ELECTROSTATIC CHARGING ELEMENTS WITHIN SAID DUCT, ASECOND DUCT EXTENDING FROM A WALL OF THE HOUSING TO A LOCATION ADJACENTTHE FEED ZONE, FEED MECHANISM IN THE FEED ZONE CONNECTED TO RECEIVESHEETS FROM BOTH DUCTS AND PASS THEM TOGETHER ALONG AN EXPOSURE PATHWHERE THEY COOPERATE WITH THE EXPOSURE STRUCTURE TO CAUSE AN IMAGE ONONE SHEET TO BE PHOTOGRAPHICALLY EXPOSED ON THE OTHER SHEET, ADJUSTABLEDIVERSION STRUCTURE MOVABLY POSITIONED ADJACENT THE FEED ZONE SO THAT ITCAN BE INSERTED IN AND WITHDRAWN FROM ZONE, AND A PASSAGEWAY FROM THEFEED ZONE TO THE EXTERIOR OF THE HOUSING, SAID PASSAGEWAY COOPERATINGWITH THE DIVERSION STRUCTURE TO CAUSE A SHEET MOVING THROUGH THE FIRSTDUCT TO BE DEFLECTED THROUGH SAID PASSAGEWAY AND OUT OF THE HOUSINGWITHOUT BEING PHOTOGRAPHICALLY EXPOSED, WHEN THE DIVERSION STRUCTURE ISINSERTED IN THE FEED ZONE.